For the first time in December of 1983 a solid phase process had been described by two Russian authors (S. A. Chuvpilo and V. V. Kravchenko: Bioorg. Khim 9 (12) (1983) 1634-1637), however only for sequencing long DNA-segments and by using a commercially available DEAE-paper (DE 81 of the company Whatman). It consists of the steps: (1) immobilization of the 5'- or 3'-marked DNA-fragment on the carrier; (2) washing; (3) chemical modification reactions without excess reagent surplus (i.e., not in a reaction vessel) in accordance with Maxam and Gilbert (A. M. Maxam and W. Gilbert: Methods in Enzymol. 65 (1980) 499-560); (4) Washing; (5) Piperidine reaction under standard conditions (only 20% loss of the radioactive fragments); (6) Washing; (7) 2.times. elution of the fragments from the carrier with 1M NaCl at 60.degree. C.; (8) Ethanol precipitation for precipitating the material and the 2.times. washing with 90% ethanol.
The disadvantages of this process are:
The very poor mechanical stability of the DE 81 paper makes the manipulation of the carrier in watery buffers very difficult (above all at high temperatures). A rapid tearing, dissolving and peeling of the carrier occurs.
The modification reactions used result in almost 100% losses in the A+G-, T+C- and C-reactions, if they are performed in reaction vessels for example, in microcentrifuge tubes with excess reagent.
Due to the poor mechanical characteristics of the DE 81 carrier, the simultaneous sequencing of large quantities of nucleic acid fragments is not possible in a reaction vessel.
In all, 8 operations are required, whereby the operation of the ethanol precipitation (no. 8) is principally not suitable for an automatic mode of operation.
Oligonucleotide=8 units cannot be sequenced in accordance with this process, since the first 5'-permanent nucleotides are lost during the reprecipitation so that the sequence samples cannot be completely read.
On account of all of the described disadvantages, the described process can firstly not be automated and secondly no large quantities can be simultaneously sequenced even with a manual operation. Short nucleic acid fragments (DNA- and RNA-oligomers) cannot be sequenced at all.
Devices for performing solid phase sequencing are not known heretofore. The known sequencing process can generally be performed in commercially obtainable vessels like, for example, microcentrifuge tubes and customary laboratory glass devices. The simultaneous sequencing of a plurality of fragments is principally possible, however the operation of the process is not economical and the danger of confusing immobilized nucleic acid fragments is very large.